public GuestsViewModel() { Title = "Browse"; Guests = new ObservableCollection <Guest>(); LoadGuestsCommand = new Command(async() => await ExecuteLoadGuestsCommand()); MessagingCenter.Subscribe <NewGuestPage, Guest>(this, "AddGuest", async(obj, guest) => { var _guest = guest as Guest; Guests.Add(_guest); await GuestDataStore.AddMemberAsync(_guest); }); MessagingCenter.Subscribe <GuestListPage, Guest>(this, "DeleteGuest", async(obj, guest) => { //var _guest = Guests.Where((Guest arg) => arg.PersonalCode == guest.PersonalCode).FirstOrDefault(); var _guest = guest as Guest; Guests.Remove(_guest); await GuestDataStore.DeleteMemberAsync(_guest); }); }